STUDY ON THE FIXATION COMPRESSIVE DEFORMATION OF POPULUS USSURIENSIS IN THE TRANSVERSE DIRECTION BY HIGH TEMPERATURE STEAM TREATMENT Study on the Cold Resistance of 9 Provenances of Populus ussuriensis Kom Changes in Antioxidative Enzymes Parameters of Populus ussuriensis Seedlings after Spaceflight of the Seeds Study on Gene Resources in Populus ussuriensis Effect of Arbuscular Mycorrhizal Fungi on the Growth of Populus ussuriensis Rapid Prediction of the Weight Percentage Gain of Acetylated Wood Using Near Infrared Spectroscopy Purification and Identification of Populus ussuriensis Genomic DNA